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This paper completes and comments on some aspects of our previous publications. In ref [1], we have derived a set of space-time transformations referred to as the extended space-time transformations. These transformations, which assume the…

General Physics · Physics 2008-03-27 Joseph Levy

In this two-part paper we propose an extension of Connes' notion of even spectral triple to the Lorentzian setting. This extension, which we call a spectral spacetime, is discussed in part II where several natural examples are given which…

Operator Algebras · Mathematics 2017-03-14 Fabien Besnard , Nadir Bizi

In this short note we clarify a link between anisotropic-scaling scenarios and Finsler spacetimes. Generalizing earlier analysis it is shown that the kinematics of propagating particles (in the sense of geometrical optics) can be described…

General Relativity and Quantum Cosmology · Physics 2009-10-19 Lorenzo Sindoni

The gravitational deflection of light is a critical test of modified theories of gravity. A few years ago, Gibbons and Werner introduced a definition of the deflection angle based on the Gauss-Bonnet theorem. In more recent years, Arakida…

General Relativity and Quantum Cosmology · Physics 2023-12-12 Flavio C. Sánchez , Armando A. Roque , Benito Rodríguez , Javier Chagoya

The metric-affine variational principle is applied to generate teleparallel and symmetric teleparallel theories of gravity. From the latter is discovered an exceptional class which is consistent with a vanishing affine connection. Based on…

General Relativity and Quantum Cosmology · Physics 2018-09-17 Jose Beltran Jimenez , Lavinia Heisenberg , Tomi Koivisto

We investigate the observational effects of a quintessence model in an anisotropic spacetime. The anisotropic metric is a non-rotating particular case of a generalized Godel's metric and is classified as Bianchi III. This metric is an exact…

Cosmology and Nongalactic Astrophysics · Physics 2014-07-23 W. Miranda , S. Carneiro , C. Pigozzo

In a previous paper [gr-qc/0104001; Class. Quant. Grav. 18 (2001) 3595-3610] we have shown that the occurrence of curved spacetime ``effective Lorentzian geometries'' is a generic result of linearizing an arbitrary classical field theory…

General Relativity and Quantum Cosmology · Physics 2009-11-07 C. Barcelo , S. Liberati , Matt Visser

We explore singularity-free and geodesically-complete cosmologies based on manifolds that are not quite Lorentzian. The metric can be either smooth everywhere or non-degenerate everywhere, but not both, depending on the coordinate system.…

General Relativity and Quantum Cosmology · Physics 2023-03-02 Bob Holdom

This article is an exposition of four loosely related remarks on the geometry of Finsler manifolds with constant positive flag curvature. <p> The first remark is that there is a canonical Kahler structure on the space of geodesics of such a…

Differential Geometry · Mathematics 2007-05-23 Robert L. Bryant

We hereby show that the Kasner spacetime turns out to be singularity-free in Einstein's conformal gravity in vacuum or in presence of matter. Such a statement is based on the regularity of the curvature invariants and on the geodesic…

General Relativity and Quantum Cosmology · Physics 2019-06-24 Leonardo Modesto , Hui-Yu Zhu , Jun-Yan Zhang

In Einstein's gravitational theory, the spacetime is Riemannian, that is, it has vanishing torsion and vanishing nonmetricity (covariant derivative of the metric). In the gauging of the general affine group ${A}(4,R)$ and of its subgroup…

General Relativity and Quantum Cosmology · Physics 2008-11-26 F. W. Hehl , J. D. McCrea , E. W. Mielke , Y. Ne'eman

What is the shape of space in a spacetime? One way of addressing this issue is to consider edgeless spacelike submanifolds of the spacetime. An alternative is to foliate the spacetime by timelike curves and consider the quotient obtained by…

General Relativity and Quantum Cosmology · Physics 2009-11-07 Steven G. Harris , Robert J. low

We study light-front physics and conformal symmetry, and their interplay both on and off the light cone. The full symmetry of the light cone is conformal symmetry not just Lorentz symmetry. Spontaneously breaking conformal symmetry gives…

High Energy Physics - Theory · Physics 2025-01-31 Philip D. Mannheim

The concept of time-space defined in an earlier paper of the author is a certain generalization of the so-called space-time. In this paper we introduce the concept of time-space manifolds. In the homogeneous case, a time-space manifold is a…

General Physics · Physics 2016-06-09 Ákos G. Horváth

At first we introduce the space-time manifold and we compare some aspects of Riemannian and Lorentzian geometry such as the distance function and the relations between topology and curvature. We then define spinor structures in general…

General Relativity and Quantum Cosmology · Physics 2015-06-25 Giampiero Esposito

A novel but elementary geometric construction produces on the seven-dimensional manifold of rotated spheres in Euclidean three-space a finslerian geometry whose geodesics are interpreted as the paths of free, spinning, spherical particles…

General Relativity and Quantum Cosmology · Physics 2007-05-23 Homer G. Ellis

The affine connection in a space-time with a maximally symmetric spatial subspace is derived using the properties of maximally symmetric tensors. The number of degrees of freedom in metric-affine gravity is thereby considerably reduced…

General Relativity and Quantum Cosmology · Physics 2009-03-20 Tuomas Multamäki , Jaakko Vainio , Iiro Vilja

This paper is devoted to the complete classification of space curves under affine transformations in the view of Cartan's theorem. Spivak has introduced the method but has not found the invariants. Furthermore, for the first time, we…

Differential Geometry · Mathematics 2012-01-11 Mehdi Nadjafikhah , Ali Mahdipour Shirayeh

It is shown that, on a manifold with a Finsler metric of Lorentzian signature, the lightlike geodesics satisfy the following variational principle. Among all lightlike curves from a point (emission event) to a timelike curve (worldline of…

General Relativity and Quantum Cosmology · Physics 2009-11-11 Volker Perlick

We suggest that the vacuum field equation in Finsler spacetime is equivalent to vanishing of Ricci scalar. Schwarzschild metric can be deduced from a solution of our field equation if the spacetime preserve spherical symmetry. Supposing…

General Physics · Physics 2018-05-11 Xin Li , Zhe Chang